/* ========================================
   873k.com - 八七三快建站 全局样式
   调料罐清新风：浅绿 + 纯白 + 浅黄
   ======================================== */

:root {
    --primary-green: #7CB342;
    --light-green: #AED581;
    --pale-green: #DCEDC8;
    --pure-white: #FFFFFF;
    --off-white: #F9FBF7;
    --light-yellow: #FFF9C4;
    --warm-yellow: #FFF59D;
    --text-dark: #2E3B2F;
    --text-gray: #5D6B5E;
    --border-color: #C5E1A5;
    --shadow-light: rgba(124, 179, 66, 0.1);
    --shadow-medium: rgba(124, 179, 66, 0.2);
    --transition-smooth: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
    font-size: 16px;
}

body {
    font-family: "PingFang SC", "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
    background-color: var(--off-white);
    color: var(--text-dark);
    line-height: 1.7;
    overflow-x: hidden;
}

a {
    text-decoration: none;
    color: inherit;
    transition: var(--transition-smooth);
}

ul, ol {
    list-style: none;
}

img {
    max-width: 100%;
    height: auto;
    display: block;
}

.container {
    max-width: 1400px;
    margin: 0 auto;
    padding: 0 20px;
}

/* ========================================
   顶部导航栏
   ======================================== */
.header {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    z-index: 1000;
    background: transparent;
    transition: var(--transition-smooth);
}

.header.scrolled {
    background: var(--pure-white);
    box-shadow: 0 2px 20px var(--shadow-light);
}

.header-inner {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 20px 0;
    transition: var(--transition-smooth);
}

.header.scrolled .header-inner {
    padding: 15px 0;
}

.logo {
    display: flex;
    align-items: center;
    gap: 12px;
    font-size: 28px;
    font-weight: 700;
    color: var(--primary-green);
}

.logo img {
    width: 50px;
    height: 50px;
    object-fit: contain;
}

.nav-menu {
    display: flex;
    gap: 40px;
}

.nav-menu li a {
    font-size: 16px;
    font-weight: 500;
    color: var(--text-dark);
    position: relative;
    padding: 8px 0;
}

.nav-menu li a::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--primary-green);
    transition: var(--transition-smooth);
}

.nav-menu li a:hover::after,
.nav-menu li a.active::after {
    width: 100%;
}

.nav-menu li a:hover,
.nav-menu li a.active {
    color: var(--primary-green);
}

.hamburger {
    display: none;
    flex-direction: column;
    gap: 5px;
    cursor: pointer;
    padding: 10px;
}

.hamburger span {
    width: 28px;
    height: 3px;
    background: var(--primary-green);
    border-radius: 2px;
    transition: var(--transition-smooth);
}

.hamburger.active span:nth-child(1) {
    transform: rotate(45deg) translate(6px, 6px);
}

.hamburger.active span:nth-child(2) {
    opacity: 0;
}

.hamburger.active span:nth-child(3) {
    transform: rotate(-45deg) translate(6px, -6px);
}

/* ========================================
   页脚
   ======================================== */
.footer {
    background: linear-gradient(135deg, var(--primary-green) 0%, var(--light-green) 100%);
    color: var(--pure-white);
    padding: 60px 0 30px;
}

.footer-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 40px;
    margin-bottom: 40px;
}

.footer-section h4 {
    font-size: 18px;
    margin-bottom: 20px;
    position: relative;
    padding-bottom: 10px;
}

.footer-section h4::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 40px;
    height: 2px;
    background: var(--pure-white);
}

.footer-section ul li {
    margin-bottom: 12px;
}

.footer-section ul li a {
    color: var(--pure-white);
    opacity: 0.9;
}

.footer-section ul li a:hover {
    opacity: 1;
    padding-left: 8px;
}

.footer-contact p {
    margin-bottom: 12px;
    display: flex;
    align-items: center;
    gap: 10px;
}

.footer-bottom {
    border-top: 1px solid rgba(255,255,255,0.3);
    padding-top: 30px;
    text-align: center;
    font-size: 14px;
    opacity: 0.8;
}

/* ========================================
   动画效果
   ======================================== */
.fade-in {
    opacity: 0;
    transform: translateY(30px);
    transition: opacity 0.6s ease-out, transform 0.6s ease-out;
}

.fade-in.visible {
    opacity: 1;
    transform: translateY(0);
}

/* ========================================
   按钮样式
   ======================================== */
.btn {
    display: inline-block;
    padding: 14px 32px;
    border-radius: 50px;
    font-size: 16px;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition-smooth);
    border: none;
}

.btn-primary {
    background: linear-gradient(135deg, var(--primary-green) 0%, var(--light-green) 100%);
    color: var(--pure-white);
}

.btn-primary:hover {
    transform: translateY(-3px);
    box-shadow: 0 10px 30px var(--shadow-medium);
}

.btn-secondary {
    background: var(--pure-white);
    color: var(--primary-green);
    border: 2px solid var(--primary-green);
}

.btn-secondary:hover {
    background: var(--primary-green);
    color: var(--pure-white);
}

/* ========================================
   卡片样式
   ======================================== */
.card {
    background: var(--pure-white);
    border-radius: 16px;
    overflow: hidden;
    box-shadow: 0 4px 20px var(--shadow-light);
    transition: var(--transition-smooth);
}

.card:hover {
    transform: translateY(-8px);
    box-shadow: 0 15px 40px var(--shadow-medium);
}

/* ========================================
   响应式设计
   ======================================== */
@media (max-width: 1024px) {
    .footer-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (max-width: 768px) {
    .nav-menu {
        position: fixed;
        top: 80px;
        left: -100%;
        width: 100%;
        height: calc(100vh - 80px);
        background: var(--pure-white);
        flex-direction: column;
        padding: 40px;
        gap: 20px;
        transition: var(--transition-smooth);
    }

    .nav-menu.active {
        left: 0;
    }

    .hamburger {
        display: flex;
    }

    .footer-grid {
        grid-template-columns: 1fr;
    }

    .container {
        padding: 0 15px;
    }
}